One type of connection to provide electrical contact between a printed circuit board and another device uses a pin formed of electrically conductive material which is inserted into a plated-through hole in the circuit board. Often, the pin is soldered into the hole to maintain a good electrical connection between the pin and the hole. However, for some applications, pins which may be removed and reinserted repeatedly are desirable. Removal of the pin is inconvenient and time consuming if the connection has been soldered.
One type of removable connection known in the prior art is the press-fit connection. With this connection, the pin is pressed into the hole in the circuit board and retained therein by frictional engagement between the pin and the hole walls. However, the pin may also be removed upon application of sufficient force.
Press-fit pins must remain in the hole under most conditions and maintain good electrical contact with the plating of the hole, yet must be removable if necessary without damaging or destroying either the pin or the hole. One attempt known in the prior art to meet these requirements has been to utilize pins with a compliant portion which yields slightly upon being forced into the hole. See for example, U.S. Pat. No. 4,728,164 to Lemmens et al., U.S. Pat. No. 4,733,465 to Tanaka, or U.S. Pat. No. 4,740,166 to Barnhouse. These prior art pins have a configuration providing one or more hinge areas that bend or flex as the pin is inserted in the hole, allowing the pin to compress to fit into the hole.
A disadvantage to configurations that bend or flex is that the pin can shear or split near the flexure area. Shearing or splitting is especially a problem if the pin is forced into a hole that is too small, overstressing the pin. Additionally, the pin can damage the plating in the circuit board hole by repeated movement of the pin's exterior surfaces relative to the plating as the pin flexes. Such movement can occur from thermal expansion and contraction due to temperature changes or from physical forces exerted on the pin, as when the pin is being inserted or removed. Eventually, the plating and even the pin itself can degrade so that a good electrical contact can no longer be maintained. The substrate of the circuit board may also be damaged.